Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
  • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids

Definitions

• THIS INVENTION relates to corrosion inhibitors and compositions containing them.
• heat exchange systems for example domestic central heating systems, motor vehicle cooling systems and the like
• a heat exchange fluid comprising large quantities of water.
• the fluid comes into contact with a number of different metals for example solder, copper, brass, steel, cast iron and/or aluminium corrosion problems may become acute both because of the need to protect each of the metals individually against corrosion and also because electrolytic cells may be set u p between the different metals present.
• the problem is further exacerbated by the need in many parts of the world to include an antifreeze component in the heat exchange fluid during the winter in order to protect the heat exchange fluid from freezing during cold weather.
• Common antifreeze components are organic liquids which reduce the freezing point of water and are relatively stable to the working conditions encountered; they include methanol (which is however, somewhat volatile and thus tends to be lost by evaporation) ethylene glycol and propylene, glycol.
• methanol which is however, somewhat volatile and thus tends to be lost by evaporation
• ethylene glycol The most common is ethylene glycol; this may if desired be used in admixture with methanol and/or propylene glycol.
• Other organic liquids for example ethanol may be used but considerations of cost effectiveness and volatility generally favour ethylene glycol.
• a corrosion inhibitor comprises a triazole, preferably 2 to 50 parts by weight, an alkali metal borate preferably in an amount sufficient to give a boron content of 5 to 60 and more preferably 10 to 30 parts by weight, an alkali metal benzoate or homologue thereof, preferably 100 to 500 and more preferably 150 to 300 parts by weight, an alkali metal silicate sufficient to provide water soluble silicate preferably in an amount of 1 .
• the composition may if desired by incorporated into an antifreeze composition by dissolving it in 10,000 parts by weight of an antifreeze component as aforesaid, especially ethylene glycol.
• the antifreeze composition may if desired contain a small amount of water to improve the solubility of the corrosion inhibitor, colouring matter, anti-foaming agents and other materials if desired.
• the antifreeze composition may be diluted in a ratio of 2:1 and preferably 1:2 to 1:5 by volume with water to produce a heat exchange fluid suitable for use in motor vehicle cooling systems.
• the dibasic acid should have 9 to 12 carbon atoms.
• Sebacic acid is suitably present and very suitably a mixture of dibasic acids having 9 to 12 carbon atoms may be employed.
• the triazole is suitably benzotriazole or tolyltriazole.
• the alkali metal silicate is suitably an alkali metal metasilicate.
• a suitable homologue of the benzoate is the toluate.
• the alkali metal borate may be for example a sodium tetraborate.
• the alkali metals of the inhibitor are suitably sodium or potassium or a mixture thereof.
• Antifreeze formulations were prepared by dissolving the appropriate compounds in the indicated amounts in monoethylene glycol. Concentrations are in % by weight of the total composition.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Anti-Oxidant Or Stabilizer Compositions (AREA)

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Publications (2)

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Cited By (8)

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Citations (2)

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• 1980
  • 1980-03-12 GB GB8008297A patent/GB2075483A/en not_active Withdrawn
• 1981
  • 1981-02-13 DE DE8181300596T patent/DE3161724D1/de not_active Expired
  • 1981-02-13 EP EP81300596A patent/EP0035834B1/de not_active Expired
  • 1981-02-13 AT AT81300596T patent/ATE5734T1/de not_active IP Right Cessation
  • 1981-02-20 US US06/236,041 patent/US4382008A/en not_active Expired - Fee Related
  • 1981-02-20 AU AU67524/81A patent/AU542305B2/en not_active Ceased
  • 1981-02-24 ZA ZA00811242A patent/ZA811242B/xx unknown

Patent Citations (2)

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